How to Make Vertical 9:16 Clips for Shorts and Reels

Shorts, Reels, and TikTok all want full-frame 9:16 video. Generating directly in vertical is far better than cropping a 16:9 clip after the fact, because cropping throws away resolution and often cuts your subject's head off. This guide covers getting clean vertical output from all three major models.

What you need

• An account on Runway, Kling, or the Gemini app with Veo
• A prompt or source image framed for a tall composition
• A target platform in mind (Shorts, Reels, TikTok)
• About 5 minutes

Step 1: Set the aspect ratio before you generate

In every tool, the aspect ratio control sits near the prompt box. Set it to 9:16 first. Doing this before generation means the model composes for a tall frame, placing your subject vertically rather than centering a wide shot.

Step 2: Compose the prompt for a tall frame

Vertical frames favor a single subject and vertical movement. Mention full-body or close-up framing and avoid wide panoramas that only make sense in landscape.

vertical 9:16 shot, full-body view of a runner sprinting
toward camera on a city street at night, neon reflections,
handheld follow shot

Step 3: Generate and check safe zones

Render the clip, then mentally overlay the platform's UI. If the runner's feet or face land where the caption bar or the share buttons sit, regenerate with a tighter or higher composition.

Step 4: Verify the exported dimensions

Before uploading, confirm the file is truly vertical. A quick check with ffprobe shows the resolution; you want height greater than width, such as 720x1280 or 1080x1920.

Step 5: Upload to the platform

Upload the native vertical file directly. Because you never cropped, the clip fills the screen edge to edge at full resolution and your subject stays inside the safe zone.

Result

A vertical runner clip that fills a phone screen and keeps the action clear of the caption bar. Setting 9:16 before generating, not after, is the one habit that saves you from blurry cropped uploads.